How The Design of Tenochtitlan Was Ahead of its Time

Bloodthirsty. Engineers. Planners. Violent. Cunning. Pioneers. Innovative. All of these words may describe the Aztecs, and they all hold a kernel of truth.

Jan 28, 2023By Dennis Lynch, BSc Civil Engineering

how tenochtitlan design was ahead of its time


Tenochtitlan is the ancient name for the current capital of Mexico – Mexico City. It is from a time when the Aztec people ruled the land with jaguar skins, obsidian swords, and ritual sacrifices to bloodthirsty gods – but it might surprise you that their urban planning, design, and engineering works were exceptional. So exceptional that conquistadors were amazed by its greatness. From aqueducts to drawbridges to dikes to the layout of the cityscape itself, the design of Tenochtitlan was ahead of its time.


The Aztecs Arrive in Tenochtitlan

aztec floating gardens
Depiction of Aztec Chinampas, via


The Aztecs were a fragile alliance of three city-states. The most influential was Tenochtitlan, built in the middle of then-Lake Texcoco. This location was naturally defensible as a large island quite a distance from the shoreline of the lake. The city was built by people known as “Mexica.” The Mexica chose the location due to the fact that once they arrived at the valley where Tenochtitlan would be founded, nearly every other city-state claimed areas at the edge of the lake and no one wanted the drab island. The other city-states found the edges of the lake to be better for the types of agriculture that grew in 1400s Mexico, such as corn, beans, and squash.


Since the Mexica were late to finding a home in the area, they took the only place they could – an island that did not have the capabilities of growing the food they needed. If it were capable of doing so, the other cities would have already claimed it. But ingenuity struck the Mexica. With help from a neighboring city-state, the Mexica found a way to build floating gardens. The gardens consisted of woven reeds in a basket-like pattern which were covered in a few feet of mud. So that the gardens would not float away, they were then anchored to trees and provided space for canoes to pass via a canal.


tenochtitlan birds eye view
A Bird’s Eye View of Tenochtitlan after its development,


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After the introduction of the floating gardens, called “chinampas,” the Aztecs turned their undesirable rock of an island city into a fortress. Now they had water working for them, not against them. The Aztecs grew the usual agriculture for the area – corn, beans, and squash. But they also grew more than just the staple crops, as the Aztecs also grew tomatoes, peppers, and even flowers! Thanks to the wonderful supply of fresh water that even conquistadors noticed, the Aztecs could grow food throughout the year. They then harvested this food about seven times each year, a considerable amount.


The Aztecs further mastered water with dams and sluice gates. One of these incredible dams is the Nezahualcoyotl Dike mentioned previously. The combination of all of this hydro-engineering infrastructure not only permitted great harvests but also an adept drainage system. The dike itself had a major role in reducing flooding from the saltwater of Lake Texcoco up to the freshwater of Lake Tenochtitlan. Most importantly, the dike appears to have performed its function. There are no records of flooding in Tenochtitlan from Lake Texcoco until after the conquistadors arrived and damaged the dike.


The Nezahualcoyotl Dike

aztec map mexico 1519
Map of Lake Texcoco and the surrounding area. Notice the Dike of Nezahualcoyotl, via


The most amazing piece of engineering for Tenochtitlan was the Nezahualcoyotl Dike, which split the salt waters of Lake Texcoco from the fresh waters of Lake Tenochtitlan. The Aztec capital was located in the freshwater portion of the two lakes, seated on a defensible and large island. The dike was approximately 16 kilometers (about 10 miles)! For a structure of that size, it would take an average person just over three hours to fully traverse the dike from end to end. The dike typically kept the water level on the freshwater side about two meters (about 10 feet) above the saltwater lake on the opposite side. The structure provided flooding control and desalination of the freshwater portion of the once-combined lake.


This dike, among many other engineering features, allowed the Aztecs to dominate their neighbors and become only conquerable by an alien colonial power. Common culture paints the Aztecs as a homogeneous, strong, and vast empire, but its ad hoc and shaky political situation was quite the contrast to the well-constructed Nezahualcoyotl Dike.


The Triple-Alliance Under Tenochtitlan

aztec founding tenochtitlan
The Founding of Mexico City by Jose Maria Jara, depicting the founding of Tenochtitlan, 1889, via


The City of Tenochtitlan did not master the waters and their enemies alone. The other two city-states of the shaky alliance are Tlacopan and Texcoco. Tlacopan was situated nearer to Tenochtitlan. It stood northwest of the island on the shore of the freshwater Lake Tenochtitlan. Texcoco was situated farther away in the opposite direction, on a river that fed into the salty Lake Texcoco. The group rose together in power due to the nature of power in 1300s Mexico.


Each city-state in and surrounding Lake Texcoco and its tributaries had a similar culture of military violence against neighbors. The result of this violence for the victors was multiple wives as tributes. In the same vein, women were also given as gifts to political allies as wives. The result of this confusing mixing of bloodlines of diplomatic rivals resulted in a battle royale of potential heirs just about every time a leader perished. The “kings” of these city-states were called tlàtoani, which means “speaker” or “mouthpiece.” In 1426, the tlàtoani of Azcapotzalco died.


Azcapotzalco was the most powerful of the city-states in the area at the time. A power vacuum quickly appeared, with Azcapotzalco leaderless and ripe for another succession crisis. What happened next catapulted the Triple Alliance into power.


aztec leader tlatoani cuauhtemoc
Depiction of a Tlatoani named Cuahtémoc, via


The tlàtoani of Tenochtitlan was an heir to the Azcapotzalco throne. His name was Itzoatl, which means “Obsidian Snake.” Itzoatl did not have a great claim to the throne, as he was the son of an enslaved woman and a prior king. However, he was diplomatically witty and found allies to which one would not jump directly. The Tenochtitlan tlàtoani went after weaker city-states that could not rise to power of their own accord. He also conveniently sought allies who were previously harmed in some manner by the powerful Azcapotzalco.


This is where he found Tlacopan and Texcoco as allies. The three city-states worked together as a coalition and defeated the powerful and leaderless domineering Azcapotalco. This confirmed the Triple Alliance as the great power of the region.


Human Sacrifice (And Urban Planning)

nuremberg map tenochtitlan
Map of Tenochtitlan from Nuremberg, via Library of the University of British Columbia


As popular culture and world history education in high school has often reminded us, human sacrifice was at the center of Aztec culture. Above is the map of Tenochtitlan published in Nuremberg, which laid within the Holy Roman Empire in 1524. While the map is highly stylized, the center of the city draws one’s attention. It clearly shows the Great Temple (or Templo Mayor) as the center of the entire city.


The Templo Mayor appears to have been constructed soon after the Mexica people arrived on Tenochtitlan. Evidence shows that 1325 was when the temple was built. It was dedicated to the Aztec god Huitzilopochtli.


This temple firmly weaves two important aspects of the Aztec people together – their engineering feats and their large-scale human sacrifice. Soil mechanics studies proved that, like the chinampas that were built, the Templo Mayor was constructed on an artificial island. The god that this temple was dedicated to, Huitzilopochtli, is more or less the god of the Aztecs and the Mexica people.


aztec templo mayor
An engraving of the Templo Mayor from 1684, via Library of the University of British Columbia


Huitzilopochtli can be identified as the Aztec Sun God, but also their God of War. The Aztecs believed the god needed daily ritual sacrifice. It was so important that they developed a word for it: tlaxcaltiliztli. As one would expect, this nourishment would be provided with blood and human hearts.


Again, the sacrificial slaughter of people stands in direct contrast to the minds needed to design the city of Tenochtitlan. The city is very clearly grid-like, similar to Manhattan in New York City or the French Quarter in New Orleans. The grid was uniform and divided the city into four major areas. However, the temple dedicated to a bloodthirsty god had another use: it tracked the cycles of the sun.


Though the cycles appear in an unnatural 13 or 20-day cycle, the Templo Mayor seemed to be used as a calendar of sorts. However, it later appeared that these cycles of the sun with the use of the local landmarks and temples as markers were for agricultural means. This would have helped the Aztecs reap those seven harvests a year. And perhaps most interestingly enough, the temples were designed to catch both the summer and winter solstices. When the sun would rise on those days of the year, it would rise directly between the two temples; it would have been an ethereal sight. Unless you were a ritual sacrifice.


aztec sacrifice depiction
Depictions of Aztec sacrifices from the Codex Magliabechiano CL. XIII.3, (B. R. 232), via


The Aztecs clearly had a huge demand for human labor for their rituals. Since volunteering for such a thing was likely as uncommon as today, especially in such large amounts, the Aztecs used prisoners of war. As the Mexican Valley at this time was clearly often riddled with violence and blood, prisoners of war were common. Since the Aztec Triple-Alliance was the uncontested ruler of the area after their defeat of Azcapotzalco, they had plenty of prisoners to choose from.


The need for large-scale human sacrifice was more of a result of the Triple Alliance’s pursuit of power, rather than a direct desire to commit massacres. To maintain its position as the most powerful nation in the area, the alliance chose to rule through fear – as many empires do. Just like the Nazis sacrificed hundreds of thousands on the Eastern Front as they pushed further into the Soviet Union to maintain control, the Aztecs did the same. And while there were songs and poems rallying against the unnecessary violence, in much the same way as the Nazis, those in power saw no other option but to continue the massacres.


map new spain
Map of New Spain by Emmanuel Bowen, 1747, via


And just like how rebellion and resistance assisted in decapitating the German Reich from the lands they invaded, the same eventually happened to the Aztecs. However, it took about a year after the death of Montezuma in 1520 for the resistance to spread. Once the Tlaxcalans and other groups of the area recognized the technological superiority in compasses, cannons, ships, and weaponry of the Spanish, they decided to join the Spanish.


And with the coalition of the Spanish and local rivals, the Aztecs fell in 1521. Tenochtitlan was sieged and raided and razed to the ground. Just as many other Native Americans died of disease, so did many Aztecs in their fortress island capital. The Nezahualcoyotl Dike was damaged. Human sacrifice ceased with the spread of Spanish Catholicism. And the city of Tenochtitlan became the capital of New Spain.

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By Dennis LynchBSc Civil EngineeringDennis is a civil engineer turned writer with a passion for history. From the Romans to the Aztecs, to the Mamluks to the Qing, He finds all facets of history fascinating. He holds a Bachelor of Science in Civil Engineering from Rutgers University in New Jersey.